Manage site collection storage limits

SharePoint Online in Office 365 is allocated a quantity of storage that's based on your number of users. The calculation works like this: 10 GB + 500 MB * number of users. The storage is available to all site collections in the tenant and serves as a central pool from which everyone can draw. You, the global admin, don't need to divvy up storage space or reallocate space based on usage. That's all handled automatically: site collections use what they need when they need it, up to a maximum of 1 terabyte (TB) per site collection. If you find that your storage pool is running low, you can always buy more storage through the SharePoint Online admin center at a cost per gigabyte (GB) per month.

Use the pooled storage model

The pooled storage model is new to SharePoint Online. You can take advantage of this by setting the storage management option to "auto." When you do, SharePoint Online disregards any existing limits you previously set on your site collections and reset them all to 1 TB. New Office 365 customers will get pooled storage by default.

Manage individual site collection storage limits

If you prefer to fine tune the storage space allocated to each site collection, you can set your storage management option to "manual" and specify individual site collection storage limits. In this case, we recommend that you also set an email alert so that you and other site collection admins can be notified when site collections are nearing the storage limit.

SharePoint Online now calculates storage in gigabytes (GB) instead of megabytes (MB) and only full integers are allowed. This does not affect your total storage in SharePoint Online.

In Limit storage quota for each site collection, enter the maximum number of gigabytes (GB) to be allocated to the site collection.

Check the box to send email to the site collection administrators when the site collections approaches the storage limit. Enter a number from 1 to 100 for the percentage of the limit to reach before an email alert is triggered.

Tip You may need to update the email alert percentage based on the new converted storage metrics.

Select Save.

How SharePoint storage is calculated

The SharePoint Online storage quota has not changed but a different metric is used. Previously, SharePoint storage was calculated in megabytes (MB) and now it's calculated in gigabytes (GB), using only full integers. If you previously set your storage quota in MB, it will be converted to GB (1024 MB=1 GB) and rounded down to the nearest integer. So a value of 5000 MB becomes 4 GB. A minimum of 1 GB can be set per site collection. If you set your SharePoint Online storage quota using PowerShell, that value will be rounded up to the nearest integer GB to prevent a value of less than one GB turning into 0 GB.